Recent Posts

1

Projects, Designs, and Technical Stuff / Re: Precision Load Cell (Wheatstone Bridge) Simulator

« Last post by floxia on Today at 05:33:57 am »

Please keep me updated because I'm really interested, I have been looking for such project and would be lovely to give it a go!

2

Beginners / Re: 555 driver and Transformer questions

« Last post by Andy Chee on Today at 05:30:01 am »

can you explain to me what to look for in the schematic that shows a strong DC offset?

Examine the output driver stage that is connected to the transformer winding.

Imagine the switching device/transistor/MOSFET/IGBT/relay is permanently on, or running at high duty cycle, say 99.99%

The voltage across the transformer in such a scenario, is effectively DC.  Not all transformers are tolerant of DC, and will result in saturation of the core.  Practically this means the core will heat up, and power will no longer transfer to the secondary winding (or less power anyway).  Also once the core saturates, your switching device will effectively be switching a dead short circuit, which will kill most devices, depending on power level.

If you change the duty cycle to 50%, your circuit will still pump DC into the transformer winding, but at 50% voltage.  This may still be plenty enough to saturate the core.

In summary, you need an alternative circuit topology.

The traditional alternate topology is a centre-tapped transformer with each winding being driven push-pull.  Given you lack a centre-tap, you'll have to go with a H-bridge configuration.

Finally, you could try a large 1000uF non-polarised capacitor* in series with your transformer winding.  This circuit topology is simple, but generally low power.

(*they're hard to find, so use 2x 2000uF polarised capacitors in series, with polarities reversed back-to-back)

3

Beginners / Re: Automatic golf ball dispenser

« Last post by BTO on Today at 05:27:50 am »

Ok so moving on to the problem. I managed to get something working. I connected up a sound sensor module the Arduino, power, and a relay module. What’s the best way to connect the solenoid to the same battery via the other side of the relay. See pictures. Problem is the solenoid obviously drains too mush current. Because the leds on the Arduino take a dive. How should I best connect up the solenoid?

Ok so moving on to the problem

Yes, Lets get back to Golf and Electronics 

What’s the best way to connect the solenoid to the same battery via the other side of the relay. See pictures. Problem is the solenoid obviously drains too mush current. Because the leds on the Arduino take a dive. How should I best connect up the solenoid?

- This is a very commonly experienced problem, Your idea is to use the main power source for everything. it won't work very well.
THE SOLUTION IS...  The Solenoid needs it's own power supply which has to go through a relay and that relay will receive a signal from the Arduino,  No doubt the condition that has to be met for the relay to get the signal to be energized is that the sound sensor has to experience
a certain condition or state
DOES THAT HELP ?

4

Repair / Re: Mig welder wire feeder controller board not working

« Last post by .RC. on Today at 05:23:43 am »

Here's the Service manual for the feeder and other documentation I could find.

Thank you so much.  I did not expect this sort of information to be available.  When I bought this welder new I did not even get a manual with it.

I think i should be able to do something now, probably let the magic smoke out somewhere.

5

Beginners / Re: Automatic golf ball dispenser

« Last post by BTO on Today at 05:18:16 am »

Are you on some spectrum or something? 

You sound like the kind of person who,  at a social gathering, when someone says "I hate it when the toast falls to the floor with the jam side down" would go on to a speech about how hate is so negative and you should make the toast on the floor a positive experience.

And when, in an attempt to get away, they ask you what the time is, you would try to teach them how to make a clock ... which is always a useful skill.

The OP is interested in playing golf, not in learning Arduino.

Look, I am beginning to learn Arduino myself; I think it is useful and entertaining... for me. I do not try to shove my own things down other people's throats because I do not want golfers telling me how great golf is.  And any golfer who tries to talk me into golf, their religion or any other cult, like Linux or Apple, I am going to walk away from. Microcontroller guys can be as bad as other types of fanatics.
[/quote]

Are you on some spectrum or something?

- I don't know what you mean by this.

You sound like the kind of person who,  at a social gathering, when someone says "I hate it when the toast falls to the floor with the jam side down" would go on to a speech about how hate is so negative and you should make the toast on the floor a positive experience.

-Hmm, OK,   No, i'm the kind of person at parties that if that happened, i would say "don't worry about it, Just get another one".
However what you said is hardly toast,
YOU SAID :
"And I hate it when people come in and propose a microcontroller for something which very clearly does not require a microcontroller"

You also said you are new to Arduino programming.
well mate, you then lack the experience to know what is VERY CLEARLY required or not. You see what is clear to you now about Arduino will not be
the same thing 2 years from now.

but you do seem to have a degree of hate within you, Even your comment back to me shows that. My comment was not one of HATE, but of ADVICE.
My comment to you was not hateful but more so a comment of explanation. and let's be honest, you really should have picked up on that.

Your reply was not toast on the floor, Your reply was an expression that you don't seem to like when people do things that you don't agree with. There also seems to be a them with "Cults" for you.
Let me ask you something , Re this

And I hate it when people come in and propose a microcontroller for something which very clearly does not require a microcontroller

- But Why ? ,  Why can't someone just come in and say "Use Arduino for that, it's so cool" ?
Say they are a newb and know little to nothing.  why can't they put forward the idea ?  Why does that upset you ?
Ideas, lead to other ideas.  THAT'S LITERALLY WHAT WE ARE DOING ON THIS FORUM. To stop people from doing that is to defeat the purpose of this forum.
I know a guy at Rigol who has said to me multiple times , regarding Dave on a scope review
"I hate it when dave picks on the fonts of the scope being different"
But Why ?  Dave is expressing his opinion , and IT'S A VALID POINT
I remember when dave was tearing down (i think) MSO5000 , he gets to the PCB and it says "Innovation or nothing" and dave says
"Nothing with a LOWER CASE N"  LOL.    That's an opinion , and i agree "nothing" should be Uppercase N for the record.

But mate, even stupid ideas can lead to smart ideas down the track, but in this case an arduino is not a stupid idea, it's not necessarily necessary for his application, but it doesn't hurt to recommend it
Also the world is not binary , RE this comment

The OP is interested in playing golf, not in learning Arduino.

- No the O.P. is interested in electronics, Arduino is part of electronics.
The choices are not.. GOLF or  NO GOLF, People are not binary nor is life. and CLEARLY he is a guy who thinks outside of the box.
CLEARLY he is a guy who is interested in the finer detail, you can see this by the way he pays attention to the dispenser falling out
of alignment with the "T" after a few dispenses. Basically, he is asking for ideas to be thrown out and that's what the forum did

so.. some of say Arduino
You and other say.. You don't need that.
Fine... Throw the ideas out, Let him play with the ideas and pick which one he likes, because thats' what he asked off us.

As for this (Just quickly),

And when, in an attempt to get away, they ask you what the time is, you would try to teach them how to make a clock ... which is always a useful skill.

- You're being stupid, and .. You know you are.
But the sarcasm also shows the hate that you have .   Mate, Are you young ? How old are you approx. (to the closest 5 years).
You sound young and when you are young you tend to have hate for everything, Things tend to bug you all the time if they are not in alignment with what you want them to be.  LEARN TO ACCEPT THAT LIFE AND PEOPLE ARE THE WAY THEY ARE.

Moving forward from that dumb comment

Look, I am beginning to learn Arduino myself;

- GREAT, and as such your job should be  TO LEARN AND LISTEN.  I myself am not new to it.
But especially if you are new you need to recognize you don't have enough experience yet and have not consumed enough of the topic
to perhaps know what we are doing here.
As i said, You were technically correct, but.. there are also reasons why me and others are saying what we are saying and you need to recognize that, but irrespective of if you know or not, HATING the fact that someone i saying shows a serious flaw with you.

I do not try to shove my own things down other people's throats

- And, no one is shoving anything down his throat, They are SUGGESTIONS AND IDEAS.

because I do not want golfers telling me how great golf is.

- But even if they were to do it, You shouldn't have them.  it just means they are passionate.
Mate, i have Jehovah's witnesses coming to my door telling me how great god is,  I just understand they are passionate about god,
i don't hate them nor am i rude to them.
This problem of hate seems to lie with you, but it's also not productive to this discussion.
I'm not being rude, but in my first reply to you, i just said, don't hate , it's not a good thing. You could have just taken that as advice,
but somehow .. you couldn't.

And any golfer who tries to talk me into golf, their religion or any other cult, like Linux or Apple, I am going to walk away from. Microcontroller guys can be as bad as other types of fanatics.

Yeah mate... there seems to be a thing with you,  You make illogical jumps.
there are no cults here, no one is sacrificing virgins and putting goat heads on a pike
Comments like yours do not arise for no reason and this part

I am going to walk away from. Microcontroller guys can be as bad as other types of fanatics.

- This comment has me curious
I mean, have you been burned my electronics guys being toxic ?
Mate, i've been on forums like Stack and Arduino and so on and i've dealt with the rudest guys who have the biggest chip on their shoulder
and they are not necessarily interested in discussion but instead they just want everyone to accept their point.
Me, i don't worry about it, I just accept that this person is the way they are.

If you enjoy electronics , My advice is dont let others kill your buzz.  But i also suspect that part of the problem is with you.
You can't be so rigid to say that the O.P. cannot use Arduino or should not use Arduino for his project.
it's about experimentation, it's about learning , LET HIM BE FREE TO DO WHAT HE LIKES

but the concept is
THE MORE IDEAS THE O.P. HAS , THE MORE LIKELY THE O.P. IS TO HAVE A BETTER OUTCOME
But don't hate it for any reason. as it's not going to contribute to your as a person in any positive way.

does that make sense ?

6

Microcontrollers / Re: RIP Z80

« Last post by nimish on Today at 05:13:39 am »

Even RISC-V is kind of stuck here, CLIC isn't ratified yet either.

Not ratified, true, but frozen and very unlikely to change. It's currently in ARC (Architecture Review Committee) review, after which it needs Committee Chair and CTO sign-off, then a public review period, then the ratification vote. My guess is ratification will be around July.

Cool, I hope it'll work with the sifive/t-head/WCH implementations. I really would not want stuff like https://discourse.llvm.org/t/rfc-prestacked-annotation-to-solve-risc-v-interrupt-stacking-mess/74120 proliferating

And a standardized debug adapter interface like ARM's SWD/DAP/coresight would be great too. Who the hell wants a different *-Link for every vendor?

7

FPGA / Re: Analog video output with FPGA ?

« Last post by Jaunedeau on Today at 05:13:20 am »

Just a random thought but : if I implement on an MCU instead of an FPGA (or use and FPGA that can implement an ADC), could a 9 or 10 bit (instead of the 8 required) bits ADC plus an autocalibration routine at boot be a good solution ?

8

Programming / Re: Angle wrapping in code, "easy" problem, need to double check

« Last post by ejeffrey on Today at 05:13:17 am »

mathematical” modular arithmetic is not inherently positive either

Obviously it's a matter of terminology and the only 100% unambiguous thing is to do is show the formula, but most sources use the word "remainder" to mean the thing that C and C++ does (share the sign of the dividend) and "modulo" mean the version where the result takes the sign of the divisor.  This includes the C standard which does call the result of the % operator the "remainder."  If you do "integer arithmetic modulo N" there are only N distinct values.  in C and C++, x % N can take on 2*N-1 possible values, which means that most of the distinct values have two possible representations.  Yes, it's a choice, but pretty inconvenient if you are doing anything you call modular arithmetic.

The behavior of / and % is defined by this single identity: (a/b)*b + a%b == a

That is rather missing the point.  Everyone agrees that that the above formula has to be true for any sensible definition of %, and was required even in C89.  What C since C99 specify is that integer division truncates to zero rather than floor towards -infinity.  Once you specify division that way, in order to satisfy this formula you need to have negative numbers produce a negative remainder.  The other possible convention (and the one I would argue is far more commonly what you want) is where integer division is floor division, and the % operator acts like modulo.

9

Repair / Re: Mig welder wire feeder controller board not working

« Last post by coppercone2 on Today at 05:06:12 am »

there has got to be a better filter then a foam ear plug. maybe a fine nylon brush?

its such a dodgy construction worker hack

I don't like it because theoretically something can get stuck in the foam and scratch up the wire, and it can soak up grease and smear it on etc. I feel like a nylon brush would brush off debris and result in cleaner wire

there must be a more professional engineering solution to this using better hardware

10

FPGA / Re: Analog video output with FPGA ?

« Last post by Jaunedeau on Today at 05:05:16 am »

Hdmi to vga would be an option, and probably what I will do in early stages since I will prototype on tang nano 4k board. One problem that sourcing one that introduce low lag might be a problem on the cheap ones (e.g. one could be good, then they can change the component in the same product). Also some seems to only support full hd, and might cut some cost saving possibilities when I aims only for CGA.

Dedicated DAC seems to be the way to go... I'll use one and hope it stays available in the futur